Vox Clamatis in Deserto
Flashlight Enthusiast
- Joined
- Jul 7, 2006
- Messages
- 1,126
Not sure if I could post this on the earlier thread which has been corrupted by a tech issue and archived.
As discussed on earlier threads, the SF T1A shuts off after five minutes on the lower 25% of its brightness range. Many of us would never use those levels anyway but others, like me, would.
I tried this myself a few days ago and thought I had found the 25% spot only to have it 'disappear' a couple of tries later. After a couple of hours I gave up, I needed to get some other work done.
Last night I was at home out on the deck enjoying some quality time tracking aircraft, satellites and wildlife on a moonlit evening. I had my Surefire Mil-Spec on yellow-green to light the stuff on the table while maintaining my night vision.
The T1A was on a neck lanyard and I was comparing it to a couple of other lights for finding raccoons in the trees. After using the T1A at full brightness I turned it down to the lowest setting where it was comparable to moonlight at close range.
After several minutes I noticed that the T1A did not shut off. I timed ten more minutes with the light staying on and reset the light off and back on to the lowest setting. This time, after five minutes it shut off as advertised.
I then tried off, full brightness for a moment, then dim. Again, the light appeared to stay on indefinitely. Was this a 'Eureka!' moment, or was I imagining things?
After a couple more successful tries, I cycled the light from bright to dim, left it on and went to sleep. Several hours later, it was still on!
It seems that, on my light anyway, if the light is turned to full brightness for a moment and then to the dimmer settings, the five minute cutoff doesn not apply. However, if the light goes from off to dim, intentionally or accidentally, the timed shutoff works as advertised. I took the light off the lanyard to make sure that movement of the tailcap wasn't bumping the potentiometer just enough to keep resetting the timer.
Can anyone else replicate these results? Does the light have to go to dim from full brightness to eliminate the shutoff or does it just have to be above the 25% and then below it? Is there an Easter egg to cancel the shutoff timer altogether?
Perhaps this observed hysteresis explains why I couldn't find the 25% mark a few days ago. Or, maybe it was the Barossa Valley Shiraz.
As discussed on earlier threads, the SF T1A shuts off after five minutes on the lower 25% of its brightness range. Many of us would never use those levels anyway but others, like me, would.
I did find the level I liked was within the first 25% so it would shut off in 5 minutes. So here is the experiment I doing now. I measured the travel of the bezel and found it to be 1.75" from off to full. Figuring 25% of that gave me 0.438" (7/16"). I marked the bezel and barrel at this position and now I'm trying different settings around that mark to see how close it is, if any of that makes sense.
I tried this myself a few days ago and thought I had found the 25% spot only to have it 'disappear' a couple of tries later. After a couple of hours I gave up, I needed to get some other work done.
Last night I was at home out on the deck enjoying some quality time tracking aircraft, satellites and wildlife on a moonlit evening. I had my Surefire Mil-Spec on yellow-green to light the stuff on the table while maintaining my night vision.
The T1A was on a neck lanyard and I was comparing it to a couple of other lights for finding raccoons in the trees. After using the T1A at full brightness I turned it down to the lowest setting where it was comparable to moonlight at close range.
After several minutes I noticed that the T1A did not shut off. I timed ten more minutes with the light staying on and reset the light off and back on to the lowest setting. This time, after five minutes it shut off as advertised.
I then tried off, full brightness for a moment, then dim. Again, the light appeared to stay on indefinitely. Was this a 'Eureka!' moment, or was I imagining things?
After a couple more successful tries, I cycled the light from bright to dim, left it on and went to sleep. Several hours later, it was still on!
It seems that, on my light anyway, if the light is turned to full brightness for a moment and then to the dimmer settings, the five minute cutoff doesn not apply. However, if the light goes from off to dim, intentionally or accidentally, the timed shutoff works as advertised. I took the light off the lanyard to make sure that movement of the tailcap wasn't bumping the potentiometer just enough to keep resetting the timer.
Can anyone else replicate these results? Does the light have to go to dim from full brightness to eliminate the shutoff or does it just have to be above the 25% and then below it? Is there an Easter egg to cancel the shutoff timer altogether?
Perhaps this observed hysteresis explains why I couldn't find the 25% mark a few days ago. Or, maybe it was the Barossa Valley Shiraz.